System for automatic generation of a change schedule for a plurality of lighting means

ABSTRACT

A system, a method and a computer program for planning the operation of a plurality of lighting means are described. For example in a department store, a number of different types of lighting means, e.g. filament lamps, discharge lamps and fluorescent tube lamps, may be installed. All of these lighting means have a certain life time and eventually need to be replaced. The system, method and computer program according to the invention automatically determine a change schedule with maintenance events for changing the lighting means, which leads to overall minimum cost in a specified time interval. The user enters a plurality of parameters for each groups of lighting means, including the number of lighting means in the group, type, price and/or value for a lifetime and operating time of the lighting means, as well as a first outlay parameter for preparation outlay and a second outlay parameter for changing outlay. The optimum change schedule is calculated in a way, where in case of identical change times for different groups, the first outlay parameter is accounted for only once.

The invention relates to a system, a method and a computer program forplanning the operation of a plurality of lighting means.

In many installations, a large number of lighting means of differenttypes are used at a common location, e.g. in the same building. Forexample in a department store, a number of different types of lightingmeans, e.g. filament lamps, discharge lamps and fluorescence tube lamps,may be installed. All of these lighting means have a certain lifetimeand eventually need to be replaced.

On one hand, this can be done by exchanging single lighting means afterthey have broken down. The exchange of single lighting means in this wayhas a number of disadvantages, however. The outlay for changing alighting means is considerable and comprises preparation outlay (e.g.time and work for retrieving exchange parts, time for service personalto reach the location, time for setting up a ladder or other devices)and actual changing outlay (work and time spend for changing the brokenlamp).

It is possible to reduce the outlay by changing whole groups of lightingmeans, e.g. exchanging all lamps in one room after, say, 5% have failed.This method, however, also have some disadvantages. The current statusof the lamps needs to be observed. The normal operation of the facilitymay be interrupted during the change. Especially, the costs involvedcannot be planned.

US-A1-2002/0143421 discloses a data processing system used forperforming predictive maintenance on an equipment, for example specifiedas mechanical equipment, electrical equipment, data processing system,electronics or optical equipment. The data processing system comprises acomponent database and a maintenance personal database. A schedulerschedules maintenance for components of the equipment. The schedule isbased on the databases, elapsed time and a maintenance factor, which canbe a financial estimate on maintenance of a component. The dataprocessing system described may allow electronic commerce orbusiness-to-business among the operator of the equipment and tradingpartners such as supplier of components or repair services.

While a data processing system as above described may generally allow anoverview of necessary maintenance events and cost, there is still a needfor a planning system and a method of operation specifically adapted tothe operation of plurality of lighting means. It is therefore an objectof the invention to propose a system, a method and a computer programfor planning the operation of a plurality of lighting means, allowingmost cost-efficient operation.

This object is achieved by a system according to claim 1, a methodaccording to claim 9 and a computer program according to claim 10.Dependent claims are directed to preferred embodiments.

According to the invention, a system for automatic planning of theoperation of a number of lighting means is provided with input andstorage means for storing a plurality of parameters of the lightingmeans to be operated and computing means for calculating a changeschedule for the lighting means.

The input and storage means are preferentially provided by a dataprocessing system, comprising one or more digital computers. The inputmeans can comprise devices connected directly to a computer, such as,for example, a keyboard, a mouse, touch-screen etc. Input means can alsobe provided over a network interface. Likewise, storage means cancomprise any type of storage means known in connection with digitalcomputers such as magnetic discs, random access memory, optical devicesetc. Also, storage means can be provided over a computer network.

The system according to the invention accepts the input of a number ofparameters describing the lighting means to be operated. The lightingmeans in one location are divided into a plurality of groups, where eachgroup comprises lighting means of the same type. For each groupparameters are stored indicating the number of lighting means in thegroup, type and/or price and life expectancy, and an operating time ofthe lighting means.

Further, a first and a second outlay parameter are stored. The firstoutlay parameter is representative of the outlay for preparation of achange of lighting means at the specified location, whereas the secondoutlay parameter is representative of the outlay for the actual changingof a lighting means. Further parameters may be used to provide moreinformation about the lighting means.

The computing means use these parameters to calculate a change schedulefor the lighting means. According to the invention, the change scheduleis calculated such in a given time interval (optimization interval) thetotal cost for all groups are minimized. According to the invention,cost-effective operation can be achieved by simultaneously changing allof the lighting means of a group, and taking into consideration the costfor preparation for a change of lighting means at the specifiedlocation, where the preparation outlay will be the same, regardlesswhether the lighting means of just one, or of several groups areexchanged.

To achieve the latter, the computing means compute for each group thegroup costs for change and replacement of lighting means; and in case ofidentical change times for different groups account for the first outlayparameter, which represents outlay for preparation, only once.Therefore, in a cost-optimized change schedule, identical change timesfor different groups of lighting means will be provided in those cases,where the cost saved by preparing a change of lighting means at thelocation only once (e.g. cost/time for maintenance personal to arrive atthe location, cost/time for transporting replacement lighting means tothe location, cost/time for providing necessary equipment at thelocation) will exceed the additional cost incurred by exchanginglighting means before the actual life expectancy is reached, whichultimately may result in a higher number of changes within theoptimization interval.

With the system, method and computer program according to the inventionthere is provided a means for an operator of a plurality of lightingmeans for efficiently planning operation of the lighting means, andscheduling exchange times to reduce cost to a minimum.

According to a development of the invention, database means are providedto store a number of lighting means types. For each type of lightingmeans, a number of parameters can be stored, e.g. a price and a valuefor an expected lifetime of the component. By employing such databasemeans, parameter input into the system is facilitated for the user,because parameters like price and lifetime of a product can be looked upin the database rather than having to be provided by the operator. Up todate product information may be provided by the manufacturer of thelighting means.

In a major development of the invention, substitution means are providedfor determining at least one alternative lighting means type for thepresent lighting means type of at least one of the groups. Thealternative lighting means type will be able to replace the actuallighting means and thus have e.g. an identical socket and produce(within a tolerance), the same colour and a amount of light, but willdiffer in price, lifetime value and/or power consumption from thepresent lighting means type. During calculation of the change schedule,a possible exchange of lighting means types is evaluated. In case theexchange leads to an overall total of cost which is lower than withoutthe exchange, the optimum change schedule calculated will comprise theexchange. This can be presented to the user in form of a proposal,indicating the cost that can be saved by the exchange.

While the above described substitution can already be beneficial if onlylifetime and price of a lighting means are considered (because, forexample, a different lighting means, although more expensive, may have alifetime that fits better into the change schedule) further advantagesarise if the cost of power consumption is additionally accounted for.Calculation of a cost optimum change schedule will reveal, e.g., whetherthe higher unit price for an energy saving lamp is justified for acertain group or not.

It is preferred that data storage means are provided for storing anumber of projects. Each project comprises a plurality of groups oflighting means disposed at one location. Preferably, the system can beaccessed by a number of persons, who can each manage one or moreprojects. The system can be made accessible over a computer network toreceive inputs and direct outputs over the network. Most preferably, thesystem can be provided as a client/server application, where a servercomputer connected to a network provides the application for a number ofclients also connected to the network.

According to a development of the invention, the calculated changeschedule—usually after confirmation of the user—is stored. The systemcomprises messaging means, by which messages can be sent reminding ofupcoming scheduled changes of lighting means. These messages can be senta predetermined time in advance, so that it is possible to arrange forservice personal and required material to be available at the scheduledtime in the right location.

The computer program according to the invention allows planning of theoperation of a plurality of lighting means. The computer program maybestored on a magnetic or optical recording media. The program may beexecutable on a computer or a cluster of computers. It is preferred forthe program to be adapted to a client/server structure, where theprogram itself runs on a server computer which may be accessed byclients, especially via a computer network.

For the user interface part of the program (input routine), it ispreferred to use html or xml code. The storage routine for storage ofparameters in a database and the computing routine for calculatingchange schedule may be provided in any computer executable form.

A preferred embodiment of the invention will be describe with referenceto the attached drawings. In the drawings,

FIG. 1 shows a symbolic representation of a system for automaticplanning of the operation of a number of lighting means;

FIG. 2 shows a symbolic representation of a facility with differentlighting means;

FIG. 3 shows a symbolic diagram of the structure of a project;

FIG. 4 shows the structure of a main frame;

FIG. 5 shows a search page for searching a data base;

FIG. 6 shows a result page with data base search results;

FIG. 7 shows a project overview table;

FIG. 8 shows two examples of a cost chart with accumulated total costshown over time;

FIG. 9 shows a flow diagram of the “threshold accepting” optimisationmethod;

FIG. 10 shows a diagram of the structure of a login and registrationmodule;

FIG. 11 shows a diagram with an overview over the structure of a projectmodule;

FIG. 12 shows a diagram with detail structure of a part of the modulefrom FIG. 11;

FIG. 13 shows the detail structure of a part of the module from FIG. 12;

FIG. 14 shows a diagram with the detail structure of a part of themodule from FIG. 11;

FIG. 15 shows a diagram with the structure of a calculation module;

FIG. 16 shows a diagram with the structure of an output module;

FIG. 17 shows a diagram of the structure of a messaging module;

FIG. 1 shows a symbolic representation of the main components of asystem for planning of the operation of a number of lighting means. Thesystem comprises, on the user side, a client computer 10 connected to anetwork 12. The system further comprises, on the server side, a servercomputer 14 with a database 16, which is connected to the same network12.

Client computer 10 may be a conventional PC, generally including aprocessor, a memory and input/output devices (not shown). Computer 10also includes a network interface. An operating system is running oncomputer 10 to accept input from input devices (e.g. keyboard, mouse)and to drive output devices (e.g. a monitor). In a preferred embodiment,client computer 10 may run the Windows operating system, and hasinstalled a http client program (browser) for accessing html/xml contenton network 12. In the preferred embodiment, the browser program canexecute instructions in the JavaScript language. Possible programs aresuitable versions of Netscape Navigator or Microsoft Internet Explorer.

Computer network 12 may be a LAN, WAN or any other type of computernetwork. A large number of computers may be connected to network 12. Ina preferred embodiment, network 12 is the internet, and client computer10 and server computer 14 communicate with each other using the TCP/IPprotocol.

The server computer 14 maybe any type of computer, including aconventional PC. In the preferred embodiment, computer 12 includes ahttp server software for offering http services over network 12. Servercomputer 14 executes server side instructions in the PHP4 language. Itwill become apparent that the system will involve multiple users, andthat numerical optimization calculations will be run on server 14.Therefore, it will be appreciated that generally a server computer 14allowing fast execution of extensive calculations should be employed,possibly a multiprocessor system or even a cluster of several servercomputers.

FIG. 2 shows a symbolic representation of lighting means disposed in afacility 20. Facility 20 may be any type of facility disposed at acertain location, e.g. a industrial plant, an office building, adepartment store etc.

The lighting means within facility 20, are of several types. It may, forexample, be assumed that facility 20 is a department store, whereseveral discharge lamps are be disposed under the ceiling. Theselighting means form a first group L1. Further, in a number of places inthe department store, there are other lighting means. Conventionalfilament lamps may be disposed in several places which will here bereferred to as a second group L2. Further, in display cases of thedepartment store, halogen lamps may be used forming a third groups L3.

The system according to FIG. 1 is used to generate a schedule for theoperation of the lighting means in the facility 20 and to execute thisschedule. The aim is most cost-effective operation of facility 20 over aspecified time period which may range, for example, from a few month toseveral years.

Within the system, which will be described in detail below, facilitymanagers are able to generate a change schedule indicating at whichpoint in time lighting means within the facility need to be exchanged.

There are further functionalities for the users, which will not bedescribed on detail here. For example, facility managers can managetheir personnel for exchanging the lighting means and can obtain quotesfrom wholesale merchants for needed parts. Wholesale merchants on theother hand can log onto the system and will receive requests for quoteof lighting means and can decide to provide corresponding quotes.

The system is implemented as a computer program running on servercomputer 14 which in the preferred embodiment can be accessed overnetwork 12 via the http protocol. A number of users access servercomputer 14 over network 12, preferably the internet, from their clientcomputers. Server computer 14 stores all data entered in the associateddatabase 16 and provides users with an interface for entering andretrieving information.

The service is only available for registered users. For each user, anumber of projects can be stored. FIG. 3 shows a symbolic representationof the structure of a project “department_store_(—)01”, comprising anumber of project parts P1 a, P1 b . . . . In each part, informationabout a number of groups of lighting means, disposed at a commonlocation, are stored. In the project of FIG. 3, part P1 a representsfacility 20 from FIG. 2, with lighting means groups L1, L2 and L3 alldisposed within facility 20.

As stated above, users access server computer 14 via a browser program.Server computer 14 dynamically generates html pages to be displayed onclient computer 10. These pages have a number of control elements, suchas links, buttons, drop-down-lists, input-fields etc. The pages arelinked to each other, so that by using the control elements the usernavigates between the pages.

The structure of these pages is shown in FIGS. 10-17 in diagram form. Inthese diagrams, each page is represented by a square. Where appropriate,several pages are depicted as an oval for a better overview. Arrowsbetween pages designate possible navigation from one page to anotherpage.

Data base 16 of server computer 14 stores user date, customer data,personnel data, page contents and access permissions. Data base 16 alsostores project data input by the clients. Further, database 16 stores alarge amount of lighting means data.

The lighting means data in data base 16 comprises information about alarge variety of different lamps. For each lamp, a number of databasefields are stored comprising information such as manufacturer, productfamily, manufacture label, electrical power, light colour, lifetimevalues etc. In the preferred embodiment, the following lifetime valuesare stored for each lamps: Lifetime_conv_(—)5: Total burning time withconventional power supply until 5% of lamps have failed,lifetime_conv_(—)10: Total burning time with conventional power supplyuntil 10% of lamps have failed, lifetime_elect_(—)5: Total burning timewith electronical power supply until 5% of lamps have failed,lifetime_elect_(—)10: Total burning time with electronical power supplyuntil 10% of lamps have failed.

FIG. 10 shows the structure of a user login module. Initially, the useris presented a startpage 0.1. From the start page, a flash animation 0.9can be selected which introduces the system to the user. From the startpage, already registered users may access a login screen 0.2. Notpreviously registered users may register on a registration page 0.3,where they are shown the terms and conditions of service on a page 0.5.After successful registration (0.6), users can log in to the service.After the password is sent (0.8) successfully, a main frame 0.4 isshown.

FIG. 4 shows the main frame, as it is displayed by a client computer 10.The screen is divided into three areas as shown, a top area T, a leftarea L and a main area M. Pages can be loaded into each of these threeareas.

Within top area T of main frame 0.4, a main navigation page 0.7 isloaded. The main navigation page allows the user to access the differentmodules “project”, “profile”, “customers”, “personnel”, “report”, and“watchlist”.

FIGS. 11-14 show the structure of the project module. Page 1.0 projectnavigation is loaded into the main frame at position L and serves fornavigation within the module.

Within the module, each user can only access his own project. Users canchoose to create new projects (1.1), edit existing projects (1.2) orshow a change schedule (1.3).

FIG. 12 shows the structure of how a new project is created. Page 1.1create new project is loaded at position M into the main frame. The pageshows the user an overview of the projects already existing. Forcreation of new projects, the user can either select a correspondingwizard (1.1.1) or manual creation (1.1.2.). The user may also select tocopy an existing project (1.1.3) after which he will be presented awarning (1.1.3.1) to exercise special caution and will than be able toedit the copied project (1.2).

In the following, creation of a new project will be explained as done byusing the wizard (1.1.1). It is clear from FIG. 12 that this can also bedone manually (1.1.2).

The wizard starts with a greeting page 1.1.1.1 at position M in the mainframe. The wizard then guides the user through the creation process.

First, the user may input the project structure by creating andinputting project parts (1.1.1.2, 1.1.1.2.1) and project subparts(1.1.3, 1.1.3.1). There are a number of settings which can beindividually adjusted for each project.

For each project, the following data is input by the user and stored indatabase 16: name of the project, customer the project is associatedwith, electricity tariff of the project per kWh, travel cost for themaintenance personnel to the project location, optimisation interval inweeks.

The optmisation interval is the time period, during which operation andmaintenance of the lighting means will be optimised. The optimisationinterval can be up to 10 years.

Each project can be associated with the name of a customer. The list ofcustomers of a particular user is stored in database 16, where alsofurther customer data may be stored.

Further, default values for certain settings of the project need to beinput by the user: (a) average burning time of the lighting means perweek, or alternatively, (b) number of business days per week and averageburning time per business day, (c) time in minutes needed to change onindividual lighting means out of the project, (d) disposal cost for alighting means out of the project, (e) possibility to use energy savinglamps instead of general purpose lamps yes/no? (f) is an electronical orconventional power supply used?

It should be noted, that these values are default values only. In manycases the values will differ for different lamp groups within the sameproject. For example, the average burning time for different lamp groupsmay be quite different. However, these default values are used in a waythat they are inherited down through the hierarchical structure from theproject root down to its associated parts and subparts. Within thisstructure, the default settings may be overwritten. In cases where partsand subparts use the same settings as the entity they are associatedwith, the settings do not need to be repeatedly input by the user, butare already filled by inheritance. For example, if default parameter (a)is set to the average number of business hours per week, all groupscreated will initially have the same value (a). For most groups oflighting means this value will already be appropriate, because thelighting means are switched on only during business hours. For thosegroups, which need a different value, the default value (a) may beoverwritten.

As will become apparent later, parameters (a)-(d) will be used directlyin the optimisation. Value (e) allows the user to manually choose ifgeneral purpose lamps may be replaced by energy saving lamps. Thisdecision can only be made by the user, because only he knows if the lampmay be replaced, due to geometry and appearance of a correspondingenergy saving lamp. Value (f) will be used to determine the life time offluorescent lamps, which is dependent on the type of power supply.

For each project part and project subpart, the user gives the name ofthe part/subpart and the association of a subpart to a project part, orto project root. Further, for each part/subpart parameters (a)-(f) areinherited from the associated entity, but may be overwritten by theuser. For example, if the user chooses to create different projectsubparts for different areas of the facility, he may change the defaultvalue (c) for the time that is needed to exchange an individual lamp. Aswill be come apparent later, value (c) is again only used as a defaultvalue and may be overwritten for individual groups of lamps.

Page 1.1.1.1.1. acquisition protocol can be displayed and printed out bythe user. The printed-out sheet serves as a template for the user tocreate an inventory of all lighting means in the facility to manage. Inthis way, the user collects the data later needed to supply the neededinformation for project parts/subparts and corresponding lamp groups.

On page 1.1.1.5, data of individual groups of lighting means is entered.For each group, the following parameters need to be provided by theuser: name of the group, association with a project part/subpart, numberof lighting means in the group.

Further, each group inherits parameters (a)-(f), and these parameterscan be individually adjusted for each group if they differ from theproject default values.

Further for each group, the user needs to specify the type of lightingmeans in the group. The corresponding pages are shown in FIG. 13.

Lighting means data as stored in database 16 is described above. Basedon this information the user may specify the lighting means of aspecific group on page 1.1.5.1. FIG. 5 shows an example of acorresponding page, where the user may select the search criteriamanufacturer, type, power and colour from drop down lists. By using abutton, “start search” the server computer 14 then searches database 16for lamps matching these specification.

FIG. 6 shows an example of a corresponding search result (page1.1.1.5.2), from which the user may select the type of the current lampgroup by activating the corresponding “select” button.

Back now in FIG. 12, after inputting all project parts, subparts andcorresponding lamp groups, the user is presented with page 1.1.1.6 wherehe can choose to finish his input or to go back an edit individualinputs (not shown).

Back in FIG. 11, from the project navigation page 1.0 the user maychoose to edit a specific project. The corresponding structure is shownin FIG. 14. As becomes clear from FIG. 14, during editing of a project,the user may choose to edit or add project parts, subparts or lampgroups. Of course, the user may also edit the project data (e.g. projectname, customer, electricity tariff, travel cost) or one of the defaultvalues of a project. The user may than choose to update the project(page 1.2.1). In the course of the update, depending on the projectstatus, a re-calculation may become necessary. Also, it is possible thatchanges previously entered may affect the project status (e.g. if a newlighting means type is introduced, for which quotes need to beobtained). The user is warned about such a change, before preceding.

If the user chooses to edit a group, it is checked on page 1.2.3.1 if anewly input lighting means type can be identified within the database.

A page 1.2.4 choose status allows the user to choose the project status.The following stati are possible for a project:

1. Acquisition

The definition of areas, subareas and lamp groups is not yet finished.

2. Acquisition Finished

The acquisition has been completed, but quotes for lighting means arestill needed, so that no change schedule can be generated yet.

3. Product Control Activated

In this status, no change schedule is to be generated yet. However, ifchanges in the database occur regarding lamps that have been selected bythe user, the user wishes to receive corresponding system message.

4. Change Schedule Monitoring Activated

A change schedule has been generated and the system monitors upcomingchange dates. For imminent change dates (x days before a change days) anotify message is generated, which will become visible in the watchlistdescribed below. Additionally the user receives an electronic mailinforming him of the upcoming change date.

5. Archive

The project has been finished and declared as archived. No furtherchanges can be made, but project data can be viewed.

Users may input into the system data concerning their customers, forwhich they manage different facilities. Users who employ personnel tochange lighting means may also manage their personnel resources withinthe system. The system may use this information to generate warnings iflighting means changes are scheduled at a time where not enoughpersonnel is available. Further, the system may be used by users toobtain quotes for lighting means. Wholesale merchants may log into thesystem, receive requests for quotes and provide such quotes. Thesespecial features, although quite useful for the system, do not form partof the invention and will therefore not be further explained.

FIG. 15 shows the structure of a calculation module. Page 5.0“calculation navigation” is loaded into the main frame at position L.Page 5.1 calculation overview is loaded into the main frame at positionM. Page 5.1 calculation overview presents the user with a list of allprojects and offers for each projects to run the optimisation or draw acalculation chart. Further, a number of options can be set on page 5.3for each project, including the labour cost per hour, estimated rate ofprice increase (in percent p.a.), price for lighting means as previouslyobtained from a wholesale merchant, tolerance level for lifetime (5% or10%), i.e. after which rate of failure to exchange lighting means,lifetime adjustment factor (Default 100%) and the choice if optimisationshould comprise replacement of current lighting means with replacementlighting means.

The above mentioned lifetime adjustment factor allows the user to entera factor adjusting the lifetime value for lighting means according tothe specific environment of the managed facility. The lifetime values inthe database are determined according to IEC standards in a standardenvironment. In an actual facility, however, different influences(ambient temperature, shocks/vibrations, supply voltage variation etc.)may influence the actual lifetime of lighting means operated in thefacility. To account for these influences, users may enter acorresponding lifetime adjustment factor according to past experiences.If, for example, a user has observed that on the average lighting meansin his facility fail about 10% earlier than according to the IECstandard value given for the specific lighting means, the user may entera lifetime adjustment factor of 90%.

After the options have been set, the actual optimisation can beactivated on page 1.3.1.1.

The aim of the optimisation is to archive minimum cost for a given timeinterval. Within this optimisation time interval the total costs arecalculated as the sum of the cost of the individual groups in theproject:C _(Total) =C _(Group(1)) +C _(Group(2)) + . . . +C _(Group(i))

The costs for one group C_(Group) are calculated from the lighting meanscosts C_(Lamps), travel costs C_(Travel), personnel cost C_(Personnel),disposal cost C_(Disposal) and energy cost C_(Energy):C _(Group) =C _(Lamps) +C _(Travel) +C _(Personnel) +C _(Disposal) +C_(Energy).

The number of changes N_(Change) for the individual lamp group iscalculated from the total burn time within the optimisation interval(calculated from parameters (a) or (b) by multiplying the average burntime per week with the number of weeks in the optimisation interval) andthe appropriate lifetime value T_(Lifetime) of the lamp, considering theuser's choices for a lifetime tolerance (5% or 10%) and, for fluorescentlamps, the information whether a conventional or an electronical powersupply is used):N _(Changes) =T _(Burn) /T _(Lifetime)

It should be noted that the above given value of N_(Changes) is only anapproximation, which is only valid if lighting means are exchangedirectly after there burn time has exceeded the expected lifetime. Thisvalue of N_(changes) will therefor only serve as a starting value in theoptimisation. In the course of the optimisation, which will be describedlater, different change schedules will be evaluated, and the total costwill then be re-calculated using the actual number of changes.

For each group, the lighting means cost is calculated from the unitprice previously obtained from a wholesale merchant C_(Unit), the numberof lamps in the group N_(Lamps) and the number of changes in theoptimisation interval N_(Changes):C _(Lamps) =N _(Lamps) *C _(Unit) *N _(Changes).

The travel cost C_(Travel) is calculated from the cost for arrival anddeparture (2*C_(Route)). In case that on the same date the lightingmeans of two or more groups are exchanged, the travel cost is divided bythe number of simultaneous changes at that date:C _(Travel)=((C _(Route)*2)/N _(same) _(—) _(change) _(—) _(time1))+((C_(Route)*2)/N _(same) _(—) _(change) _(—) _(time2))+ . . . +((C_(Route)*2)/N _(same) _(—) _(change) _(—) _(time i))

The personnel cost per change C_(personnel) _(—) _(per) _(—) _(charge)for a specific group is calculated from parameter (c) of that group(time in minutes necessary to change one lamp), the number of lamps inthe group, and the average personnel.cost per time unit.

The personnel cost is calculated from the personnel cost per changeC_(Personnel) _(—) _(per) _(—) _(change) and the number of changes inthe optimisation interval N_(Changes):C _(Personnel) =C _(Personnel) _(—) _(per) _(—) _(change) *N _(Changes).

Disposal cost C_(Disposal) for each group is calculated from the numberof lighting means in the group N_(Lamps), disposal cost for lampC_(Disposal) _(—) _(lamp) and the number of changes in the time intervalN_(Changes):C _(Disposal) =N _(Lamps) *C _(Disposal) _(—) _(per) _(—) _(Lamp) *N_(Changes).

Energy costs C_(Energy) are calculated from the known electricity tariffC_(kWh), the total burn time T_(Burn) of the lighting means within theoptimisation interval, the individual power consumption of each lightingmeans P_(Lamp) and the number of lighting means in the group N_(Lamps):C _(Energy) =C _(kWh) *T _(Burn) *P _(Lamp) *N _(Lamps)

In the course of the optimisation, a change schedule is generated whichleads to a minimum of the above calculated total costs C_(Total) in theoptimisation interval. The optimisation is done by using a numericaloptimisation algorithm. In a preferred embodiment, the optimisationalgorithm employed is a variant of the known “threshold accepting”method, which is a variant of a “simulated annealing” method. Thegeneral structure of the threshold accepting method is shown in FIG. 9.Optimisation starts out with a start configuration X₀, which in thepresent case is, for example, a change schedule for the current projectas would be intuitively chosen, where the lighting means of each groupare promptly exchanged after their burn time has exceeded the knownlifetime for the given tolerance.

In the next step, the threshold T is determined as a numerical value.

Now, a new configuration Y is chosen, which is a slight change from thestart configuration X. For the given optimisation problem, this meansthat in the new configuration Y change times are chosen slightingdifferently than in the present configuration X. Since change times foran individual group usually will not be allowed to be delayed (becausethe rate of failure of lighting means would then increase above theacceptable threshold), the changed configuration Y will generally haveat least one change date for one lamp group which is earlier than in thestart configuration X₀.

In the next step, the cost function C_(Total) is evaluated for bothconfigurations X and Y. The difference is calculated and compared to thethreshold T. If the difference is less than or equal to T, the newconfiguration Y becomes the present configuration. If not, the algorithmreturns to the step before and chooses a new changed configuration Y.

Every time a cost difference between old and new configuration is foundto be below threshold T, the value of T is lowered by a predeterminedvalue x. The algorithm is repeated until no valid alternative(C_(Total)(Y)−C_(Total)(X)≦T) has been found in a predetermined numberof iterations.

It should be noted that the above describe algorithm represents only anexample of a possible implementation of the optimisation. Other methodsare possible. Depending on the number of calculations that can beeffected on server computer 14 within an acceptable response time, itmay even be possible to calculate an absolute cost minimum by using a“brute force” approach (calculating all possible scenarios and choosingthe configuration with minimum cost). A large number of furtheroptimisation strategies and algorithms known to the skilled person mayalso be employed.

The above described optimisation only optimises the times in theoptimisation interval, where whole groups of lighting means are charged.However, the user may alternatively select an extended optimisationwhere not only the change schedule itself is optimised, but the systemis also considers to exchange lamps. Database 16 contains data on alarge number of available lamps. During the extended optimisation, whichis also effected according to FIG. 9 and the corresponding explanationabove, alternative types of lighting means are determined from thedatabase 16. The alternative means have to meet certain criteria: Theyhave to fit into the same socket as the actual lighting means, need toprovide an equivalent amount of light, need to have the same lightcolour (within a predetermined tolerance) etc. The alternative lightingmeans may differ in power consumption and lifetime values from thepresent lighting means (e.g. energy saving lamps vs. conventionalfilament lamps) and will therefore have an important influence on thevalue of the cost function C_(Total). Replacement of lighting means byalternative types will be part of determining, in each iteration step ofthe optimisation, a new configuration Y.

Back in FIG. 15, the user can choose on page 5.1 calculation overviewthe option calculation chart. The corresponding page calculation chart5.2 shows a chart which allows a facility manager to determine the costwithin the optimisation interval. In the chart, cost is shown over timeas an aggregated function, where the value at a certain time correspondsto the sum of all costs incurred up to that point in time.

Examples of such calculation charts are given in FIG. 8, which willlater be described in detail with regard to optimisation examples.

For users who act as service providers providing maintenance service forlighting means at a monthly charge, the calculation chart may show asecond curve, where the total revenues are shown. This allows such usersto calculate an appropriate monthly charge.

FIG. 16 shows a report module. Here, the user can query the system forall types of information such as change plans, lighting meansinformation, cost diagrams etc.

Page 6.0 output navigation is loaded into the main frame at position Land serves as navigation offering the user the choice of page 6.1acquisition protocol, 6.2 project overview, 6.3 download lampinformation, and 6.4 data export.

Page 6.1 acquisition protocol prints out an acquisition form which canbe used to gather information about all lighting means in the facility.

Page 6.2. project overview is loaded into the main frame at position M.The page shows all projects of the current user and provides optionsregarding these projects.

FIG. 7 shows an example of such a project overview. For each project,the next scheduled change is shown. The detailed change schedule isshown after selection of corresponding link in page 6.2.1. Another linkleads to page 6.2.2 showing the user the cost diagram (FIG. 8). Afurther link leads to page 6.2.3 giving details of quotes obtained fromwholesale merchants for the lighting means in the project, which can beprinted out on page 6.2.3.1. The order list of lighting means for theproject can be viewed on page 6.2.4.

Page 6.3 download lighting means information can be accessed from page6.0 output navigation. On this page, a booklet with available lightingmeans can be downloaded by the user.

Another option on page 6.0 output navigation is data export. Thecorresponding page 6.4 allows the user to export his requests for quote,obtained quotes and detail order list. Possible export formats arecsv-files, which can be imported in Microsoft Exel, Microsoft Access orother database programs, or xml-files, which will in future be supportedby a large number of programs.

FIG. 17 shows a watchlist module. Page 7.0 watchlist is accessible fromthe main navigation page 1.0 (see FIG. 10). Page 7.0 watchlist shows allprojects and corresponding next change dates. Additionally, in aseparate group all projects are shown in which the change schedulecomprises a change date within the next 30 days.

Page 7.0.1 watchlist/system messages is loaded into the main frame atposition M directly after login of a registered user. This page shows alist of all project with change dates in the next 30 days. Also, systemmessages relevant to the user are shown.

Next, an example for managing facility 20 of FIG. 2 with the system willbe given. It should be noted, that this choice of an extremely simpleexample with only three groups has been made for illustration purposesonly. In practise, projects will involve a far larger number of groups.For the simple structure of facility 20, it is of course unnecessary todivide the project into parts and subparts. However, for illustrationpurposes the project structure given in FIG. 3 was chosen.

The relevant user is the facility manager of facility 20. This user willuse his client computer 10 to access server computer 14 with a htmlclient program, for example Microsoft Internet Explorer. Afterconnecting to the server, he will first go through registration andlogin procedure (FIG. 10). From the main navigation page 0.7, he willthan choose “project navigation”, and from corresponding page 1.0 theoption “create new project” to enter his project.

The user will than proceed with project creation (FIG. 12) by enteringthe project structure according by FIG. 3 with project part P1 a andlamp groups L1, L2 and L3. The user will enter default parameters(a)-(f), and will overwrite, where necessary, these values for theindividual lamp groups. The user will than change the status of theproject from 1 (acquisition) to 2 (acquisition completed).

In the next step, the user will place requests for quotes to obtainquotes for the lighting means used in the project from wholesalemerchants active in the system. After obtaining the quotes, the userwill select on page 1.0 project navigation the option “show changeschedule” for the project, enter his preferences on page 1.3.1 “setpreferences” and than cause the system to start optimisation.

The System will than take the entered data to determine an optimalchange schedule as explained above. For the example of facility 20, thefollowing change schedule may be the optimum determined by the server:Project: DepartmentStore_01 Part: P1a   Group L1   Group L2   Group L3*No Alternatives* Change Schedule:   Start: 1.1.2004 20.3.2004 change L21.5.2004 change L1, L2, L3 20.8.2004 change L2 . . .

The change schedule in this example was determined without consideringalternative types of lighting means. The change schedule starts on Jan.1, 2004. After about 80 days, the filament lamps in group L2 need to beexchanged. Normally, the lamps of group L2 would have to be exchangedafter another 80 days for a second time. Instead, the optimum changeschedule places the changes of all three lamp groups together beforethis date on 01.05.2004. Although in this way the lighting means ingroup L2 are exchanged before they reach the actual end of theirexpected lifetime, the total cost is still lower. This is, becausetravel cost C_(Travel) needs to be accounted for only once on Jan. 5,2004, instead of multiple times if the lamps groups were exchange ondifferent days.

FIG. 8 shows the corresponding cost chart with the accumulated totalcost C_(Total) (shown as a solid line) over time t. Between the changedates, the cost increases linearly because of power consumption. At thefirst change date, only group L2 is changed and therefore there is acomparatively small step, corresponding to the cost incurred. On thesecond change date, the step is considerably larger because all threegroups L1, L2, and L3 are exchanged.

In an alternative example for facility 20, the user has chosen that thesystem should consider alternative lighting means types. An example foran optimum change schedule would be the following: Project:DepartmentStore_01 Part: P1a   Group L1   Group L2   Group L3 *ConsiderAlternatives* Change Schedule:   Start: 1.1.2004 20.3.2004 change L2,replace with Philips   Master PL 18 W 1.5.2004 change L1, L2, L31.10.2004 change L1, L2, L3 . . .

When considering the above change schedules with and withoutalternatives in comparison, it becomes clear that the first change eventon Mar. 20, 2004 for lamp group L2 is identical. However, in the secondcase the filament lamps of group L2 are replaced by energy-saving lampswhich correspond in light colour, socket type etc. to the filament lampsof group L2. These energy-saving lamps have lower electrical powerconsumption and longer lifetime than conventional filament lamps.

However, also in the second change schedule all three groups L1, L2 andL3 are exchanged together on, although here again lifetime of lamp groupL2 has not been reached. However, by combining the change of all threegroups L1, L2 and L3 on 01.05.2004, the change intervals of the threegroups are now nearly identical, so that all following changes can beeffected for all three groups at the same time, thus saving a largeamount on cost for all subsequent changes.

FIG. 8 shows the associated cost chart as a dotted line. At the firstchange event, lighting means of group L2 are replaced by energy savinglamps. Note that the cost step at this point is considerably larger thanthe corresponding step in FIG. 18 because of the higher cost of energysaving lamps. However, after the first change event, the furtherincrease between change events, which is due to power consumption, isless because of the lower power consumption of the newly installedenergy saving lamps. At the second change event, the cost step isconsiderable because groups L1, L2 and L3 are exchanged simultaneously.However, here again the travel cost C_(Travel) are incurred only once.

It can be seen from FIG. 8, that the alternative change schedule leadsto lower overall cost in the shown time interval.

After the user has thus generated and viewed the appropriate changeschedule, he can log out of the system. The user now has a completeoverview of the necessary maintenance events in the optimisationinterval and can make corresponding arrangements. The user also has adetailed forecast of cast for this time interval.

If the user subsequently logs into the system, he will be shown page7.0.1 with his watchlist and system messages. The watchlist will show inwhich project a change event is due in the next thirty days. Also,independently of the user login into the system, he will regularlyreceive notify messages via electronic mail by the system to inform himof upcoming change events.

If the user operates facility 20 according to the change schedule, thetotal cost incurred in the optimisation interval will be at a minimum.

It should be noted, that the above describe system represents apreferred embodiment of the invention. The skilled person willappreciate that the invention can be practised in different ways.

A possible modification involves that, instead of only generating anddisplaying a change schedule, the system actively monitors the changestatus of lighting means. Effected maintenance events (change oflighting means) are entered into the system. It may be possible thatdespite the system's recommendation, a change is effected at an earlieror a later date. After entering the actual change date, the system mayre-start optimisation to check if the different change time leads torecommendation of a different change schedule with different subsequentchange times.

1. System for automatic planing of the operation of a number of lightingmeans, said system comprising input and storage means configured forinput and storage of a plurality of parameters for a plurality of groupscomprising lighting means of the same type in the same location, wherethe parameters of each group comprise at least: the number of lightingmeans in the group, the type of lighting means, and/or a price and avalue for a lifetime of the lighting means, an operating time of thelighting means, a first outlay parameter representative of the outlayfor preparation for a change of lighting means at said location, and asecond outlay parameter representative of the outlay for changing of thelighting means, said system further comprising computing meansconfigured to calculate a change schedule with change times for changingof all of the lighting means of individual groups, where said changeschedule is calculated such that in a given time interval the total costfor all groups is minimized, where said computing means are configuredsuch that for each group the group costs for replacement of lightingmeans within said time interval are calculated, and where in case ofidentical change times for different groups the first outlay parameteris accounted for only once.
 2. System according to claim 1, said systemfurther comprising database means configured to store a number oflighting means types, where for each lighting means type at least aprice and a value of a lifetime for lighting means of the lighting meanstype are stored.
 3. System according to claim 2, said system furthercomprising substitution means for determining for a present lightingmeans type of at least one of said groups at least one alternativelighting means type, where said computing means are configured tocalculate said change schedule such that said schedule comprises anexchange of said present lighting means type by said alternative type ifthe total cost for said given time interval is lower than without theexchange.
 4. System according to claim 3, where said database means areconfigured to store for each lighting means type a value for powerconsumption, and where said computing means are configured to calculatefor said given time interval the total cost, accounting for the cost ofpower consumption.
 5. System according to claim 1, where storage meansare provided for storing a number of projects, where each projectcomprises a plurality of groups of lighting means disposed at onelocation.
 6. System according to claim 5, where said input and storagemeans are configured to query the user for a plurality of defaultparameters, where for each lighting means group in the project saiddefault parameters are copied, but may be overwritten by the user. 7.System according to claim 1, where said input and storage means comprisea network interface, said system further comprising output means tooutput at least said time schedule over said network interface. 8.System according to claim 1, said system further comprising storagemeans for storing said change schedule, and messaging means forautomatically sending messages reminding of a change of lighting means.9. Method for planning the operation of a number of lighting means,where a plurality of parameters are stored for a plurality of groupscomprising similar lighting means at a common location, where theparameters of each group comprise at least: the number of lighting meansin the group, the type of lighting means, and/or a price and a value fora lifetime of the lighting means, an operating time of the lightingmeans, a first outlay parameter representative of a preparation outlayfor changing of the lighting means, and a second outlay parameterrepresentative of the outlay for changing of the lighting means, where achange schedule with changing times for change of all of the lightingmeans of individual groups is calculated, such that in a given timeinterval the total cost for all groups is minimized, where for eachgroup the group costs for change and replacement of lighting meanswithin said time interval are calculated, and where in case of identicalchange times for different groups the first outlay parameter isaccounted for only once.
 10. Computer program for planning the operationof a plurality of lighting means with an input and storage routine forinput and storage of parameters of a plurality of groups of similarlighting means at a location, where the parameters of each groupcomprise at least: the number of lighting means in the group, a type oflighting means, and/or a price and a value for a lifetime of thelighting means, an operating time of the lighting means, a first outlayparameter representative of a preparation outlay for changing of thelighting means, and a second outlay parameter representative of theoutlay for changing the lighting means, and a computing routine fordetermining a change schedule with change times for changing of all ofthe lighting means of individual groups, where the computing routinecalculates the change schedule such that in a given time interval thetotal cost of all groups is minimized, where for each group the groupcosts for change and replacement of lighting means within said timeinterval are calculated, and where in case of identical change times fordifferent groups the first outlay parameter is accounted for only once.